This invention relates generally to a making switch and more particularly to a making switch which is used in short circuit testing stations for making the short circuit current in the circuit at the correct instant.
From time to time, as part of a quality control or test procedure, it is necessary to perform short circuit tests where high currents are involved. To perform these tests, a switch is needed which can handle the high current when making the circuit. Normally, handling a high current merely means increasing the contact area; however, for performing short circuit tests and other tests, the high current must be handled in a precise timing sequence. This means that the switch must be able to make the circuit while synchronized with the rest of the test procedure. Accordingly, it will be understood that it is highly desirable to have a switch which can make a circuit and handle high current at a fast operating speed.
A making switch, true to its name, is used to make a circuit as opposed to a circuit breaker which both makes and breaks a circuit. Therefore, the making switch need not have the capacity to carry the high currents for an indefinite period of time. The making switch closes the circuit and another switch will carry the load current. Accordingly, it will be understood that it is highly desirable to provide a synchronized make switch which can be used in short circuit testing stations for making the short circuit current in the circuit at the correct instant. The switch must be capable of making high currents at constant switching times and with minimal deviation in closing time. Typically, at test stations the impulse short circuit currents and also the short time currents are mostly higher than the currents occurring in normal high voltage installations. Such ratings can be reliably handled only by special switches.
Accordingly, it is an object of the present invention to provide a make switch for use in a testing station for making the short circuit current in the circuit at the correct instant. It is also an object of this invention to provide a make switch capable of making high currents at constant switching times with a minimum deviation.